[unix-history] / usr / src / lib / libc / stdio / getc.3

.\"	@(#)getc.3	6.2 (Berkeley) %G%
.\"
.TH GETC 3S  ""
.AT 3
.SH NAME
getc, getchar, fgetc, getw \- get character or word from stream
.SH SYNOPSIS
.B #include <stdio.h>
.PP
.B int getc(stream)
.br
.SM
.B FILE
.B *stream;
.PP
.B int getchar()
.PP 
.B int fgetc(stream)
.br
.SM
.B FILE
.B *stream;
.PP
.B int getw(stream)
.br
.SM
.B FILE
.B *stream;
.SH DESCRIPTION
.I Getc
returns the next character from the named input
.IR stream .
.PP
.IR Getchar ()
is identical to 
.IR getc ( stdin ) .
.PP
.I Fgetc
behaves like 
.IR getc ,
but is a genuine function, not a macro;
it may be used to save object text.
.PP
.I Getw
returns the next
.B int
(a 32-bit integer on a VAX-11) from the named input
.IR stream .
It returns the constant
.SM
.B EOF
upon end of file or error, but since that is a good
integer value,
.I feof
and
.IR  ferror (3S)
should be used to check the success of
.IR getw .
.I Getw
assumes no special alignment in the file.
.SH "SEE ALSO"
clearerr(3S),
fopen(3S),
putc(3S),
gets(3S),
scanf(3S),
fread(3S),
ungetc(3S)
.SH DIAGNOSTICS
These functions return the integer constant
.SM
.B EOF
at end of file, upon read error,
or if an attempt is made to read a file not opened by
.IR fopen .
The end-of-file condition is remembered,
even on a terminal,
and all subsequent attempts to read will return
.B EOF
until the condition is cleared with
.IR clearerr (3S).
.SH BUGS
Because it is implemented as a macro,
.I getc
treats a
.I stream
argument with side effects incorrectly.
In particular,
`getc(*f++);'
doesn't work sensibly.
Commit	Line	Data
c8869633	1	.\" @(#)getc.3 6.2 (Berkeley) %G%
e3c5dfdb	2	.\"
898d0dd0	3	.TH GETC 3S ""
e3c5dfdb KM	4	.AT 3
	5	.SH NAME
	6	getc, getchar, fgetc, getw \- get character or word from stream
	7	.SH SYNOPSIS
	8	.B #include <stdio.h>
	9	.PP
	10	.B int getc(stream)
	11	.br
	12	.SM
	13	.B FILE
	14	.B *stream;
	15	.PP
	16	.B int getchar()
	17	.PP
	18	.B int fgetc(stream)
	19	.br
	20	.SM
	21	.B FILE
	22	.B *stream;
	23	.PP
	24	.B int getw(stream)
	25	.br
	26	.SM
	27	.B FILE
	28	.B *stream;
	29	.SH DESCRIPTION
	30	.I Getc
	31	returns the next character from the named input
	32	.IR stream .
	33	.PP
596d2e3d	34	.IR Getchar ()
e3c5dfdb	35	is identical to
596d2e3d	36	.IR getc ( stdin ) .
e3c5dfdb KM	37	.PP
	38	.I Fgetc
	39	behaves like
596d2e3d	40	.IR getc ,
e3c5dfdb KM	41	but is a genuine function, not a macro;
	42	it may be used to save object text.
	43	.PP
	44	.I Getw
	45	returns the next
12e29951 MK	46	.B int
12e29951 MK	47	(a 32-bit integer on a VAX-11) from the named input
e3c5dfdb KM	48	.IR stream .
	49	It returns the constant
	50	.SM
	51	.B EOF
	52	upon end of file or error, but since that is a good
	53	integer value,
	54	.I feof
	55	and
596d2e3d	56	.IR ferror (3S)
e3c5dfdb KM	57	should be used to check the success of
	58	.IR getw .
	59	.I Getw
	60	assumes no special alignment in the file.
	61	.SH "SEE ALSO"
12e29951	62	clearerr(3S),
596d2e3d KM	63	fopen(3S),
	64	putc(3S),
	65	gets(3S),
	66	scanf(3S),
	67	fread(3S),
	68	ungetc(3S)
e3c5dfdb KM	69	.SH DIAGNOSTICS
	70	These functions return the integer constant
	71	.SM
	72	.B EOF
12e29951 MK	73	at end of file, upon read error,
12e29951 MK	74	or if an attempt is made to read a file not opened by
e3c5dfdb	75	.IR fopen .
12e29951 MK	76	The end-of-file condition is remembered,
	77	even on a terminal,
	78	and all subsequent attempts to read will return
	79	.B EOF
	80	until the condition is cleared with
	81	.IR clearerr (3S).
e3c5dfdb	82	.SH BUGS
e3c5dfdb KM	83	Because it is implemented as a macro,
	84	.I getc
	85	treats a
	86	.I stream
	87	argument with side effects incorrectly.
	88	In particular,
	89	`getc(*f++);'
	90	doesn't work sensibly.